@ohos.usbManager (USB Manager)

The usbManager module provides USB device management functions, including USB device list query, bulk data transfer, control transfer, and permission control on the host side as well as USB interface management, and function switch and query on the device side.

NOTE

The initial APIs of this module are supported since API version 9. Newly added APIs will be marked with a superscript to indicate their earliest API version.

Modules to Import

import { usbManager } from '@kit.BasicServicesKit';

usbManager.getDevices

getDevices(): Array<Readonly<USBDevice>>

Obtains the list of USB devices connected to the host. If no device is connected, an empty list is returned. When the developer mode is disabled, undefined may be returned if no device is connected. Check whether the return value of the API is empty.

System capability: SystemCapability.USB.USBManager

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
801	Capability not supported.

Return value

Type	Description
Array<Readonly<USBDevice>>	USB device list.

Example

let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
console.log(`devicesList = ${devicesList}`);
/*
The following is a simple example of the data structure for devicesList:
[
  {
    name: "1-1",
    serial: "",
    manufacturerName: "",
    productName: "",
    version: "",
    vendorId: 7531,
    productId: 2,
    clazz: 9,
    subClass: 0,
    protocol: 1,
    devAddress: 1,
    busNum: 1,
    configs: [
      {
        id: 1,
        attributes: 224,
        isRemoteWakeup: true,
        isSelfPowered: true,
        maxPower: 0,
        name: "1-1",
        interfaces: [
          {
            id: 0,
            protocol: 0,
            clazz: 9,
            subClass: 0,
            alternateSetting: 0,
            name: "1-1",
            endpoints: [
              {
                address: 129,
                attributes: 3,
                interval: 12,
                maxPacketSize: 4,
                direction: 128,
                number: 1,
                type: 3,
                interfaceId: 0,
              },
            ],
          },
        ],
      },
    ],
  },
]
*/

usbManager.connectDevice

connectDevice(device: USBDevice): Readonly<USBDevicePipe>

Connects to the USB device based on the device information returned by getDevices(). If the USB service is abnormal, undefined may be returned. Check whether the return value of the API is empty.

1. Call usbManager.getDevices to obtain the USB device list.
2. Call usbManager.requestRight to request the permission to use the device.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
device	USBDevice	Yes	USB device. The busNum and devAddress parameters obtained by getDevices are used to determine a USB device. Other parameters are passed transparently.

Return value

Type	Description
Readonly<USBDevicePipe>	USB device pipe for data transfer.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.
14400001	Access right denied. Call requestRight to get the USBDevicePipe access right first.

Example

let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
}

let device: usbManager.USBDevice = devicesList[0];
usbManager.requestRight(device.name);
let devicepipe: usbManager.USBDevicePipe = usbManager.connectDevice(device);
console.log(`devicepipe = ${devicepipe}`);

usbManager.hasRight

hasRight(deviceName: string): boolean

Checks whether the application has the permission to access the device.

Checks whether the user, for example, the application or system, has the device access permissions. The value true is returned if the user has the device access permissions; the value false is returned otherwise.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
deviceName	string	Yes	Device name, which can be obtained from the device list returned by getDevices.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.

Return value

Type	Description
boolean	Returns true if the application has the permission to access the device; returns false otherwise. If this API fails to be called, the following error codes are returned: - 88080385: This API is not initialized. - 88080492: An error occurs when the service data packet is written. - 88080493: An error occurs when the service data packet is read.

Example

let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
}

let device: usbManager.USBDevice = devicesList[0];
usbManager.requestRight(device.name);
let right: boolean = usbManager.hasRight(device.name);
console.log(`${right}`);

usbManager.requestRight

requestRight(deviceName: string): Promise<boolean>

Requests the temporary device access permission for the application. This API uses a promise to return the result. System applications are granted the device access permission by default, and you do not need to apply for the permission separately.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
deviceName	string	Yes	Device name, which can be obtained from the device list returned by getDevices.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.

Return value

Type

Description

Promise<boolean>

Promise used to return the result. The value true indicates that the temporary device access permissions are granted; and the value false indicates the opposite. If this API fails to be called, the following error codes are returned: - 88080385: This API is not initialized. - 88080392: An error occurs when the API data packet is written. - 88080393: An error occurs when the API data packet is read. - 88080492: An error occurs when the service data packet is written. - 88080493: An error occurs when the service data packet is read. - 88080497: An error occurs when the internal logic of the service is executed.

Example

let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
}

let device: usbManager.USBDevice = devicesList[0];
usbManager.requestRight(device.name).then(ret => {
  console.log(`requestRight = ${ret}`);
});

usbManager.removeRight

removeRight(deviceName: string): boolean

Removes the device access permission for the application. System applications are granted the device access permission by default, and calling this API will not revoke the permission.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
deviceName	string	Yes	Device name, which can be obtained from the device list returned by getDevices.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.

Return value

Type

Description

boolean

Permission removal result. The value true indicates that the access permission is removed successfully; and the value false indicates the opposite. If this API fails to be called, the following error codes are returned: - 88080382: An invalid value or parameter occurs during the API operation. - 88080385: This API is not initialized. - 88080392: An error occurs when the API data packet is written. - 88080393: An error occurs when the API data packet is read. - 88080492: An error occurs when the service data packet is written. - 88080493: An error occurs when the service data packet is read. - 88080497: An error occurs when the internal logic of the service is executed.

Example

let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
}

let device: usbManager.USBDevice = devicesList[0];
if (usbManager.removeRight(device.name)) {
  console.log(`Succeed in removing right`);
}

usbManager.claimInterface

claimInterface(pipe: USBDevicePipe, iface: USBInterface, force ?: boolean): number

Claims a USB interface.

1. Call usbManager.getDevices to obtain the USB device list and interfaces.
2. Call usbManager.requestRight to request the device access permission.
3. Call usbManager.connectDevice to obtain devicepipe as an input parameter.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
pipe	USBDevicePipe	Yes	USB device pipe, which is used to determine the bus number and device address. You need to call connectDevice to obtain its value.
iface	USBInterface	Yes	USB interface. You can use getDevices to obtain device information and identify the USB interface based on its ID.
force	boolean	No	Whether to forcibly claim a USB interface. The default value is false, which means not to forcibly claim a USB interface. You can set the value as required.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.

Return value

Type

Description

number

Returns 0 if the USB interface is successfully claimed; returns an error code otherwise. The error codes are as follows: - 63: The data exceeds the expected maximum volume. - 88080385: This API is not initialized. - 88080482: An invalid value or parameter occurs during the service. - 88080484: No permission. - 88080492: An error occurs when the service data packet is written. - 88080493: An error occurs when the service data packet is read. - 88080497: An error occurs when the internal logic of the service is executed. - -1: The underlying interface fails to be called.

Example

let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
}

let device: usbManager.USBDevice = devicesList[0];
usbManager.requestRight(device.name);
let devicepipe: usbManager.USBDevicePipe = usbManager.connectDevice(device);
let interfaces: usbManager.USBInterface = device.configs[0].interfaces[0];
let ret: number= usbManager.claimInterface(devicepipe, interfaces);
console.log(`claimInterface = ${ret}`);

usbManager.releaseInterface

releaseInterface(pipe: USBDevicePipe, iface: USBInterface): number

Releases a USB interface.

Before you do this, ensure that you have claimed the interface by calling usbManager.claimInterface.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
pipe	USBDevicePipe	Yes	USB device pipe, which is used to determine the bus number and device address. You need to call connectDevice to obtain its value.
iface	USBInterface	Yes	USB interface. You can use getDevices to obtain device information and identify the USB interface based on its ID.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error.Possible causes:1.Mandatory parameters are left unspecified.2.Incorrect parameter types.
801	Capability not supported.

Return value

Type

Description

number

Returns 0 if the USB interface is successfully released; returns an error code otherwise. The error codes are as follows: - 63: The data exceeds the expected maximum volume. - 88080381: Invalid interface operation. - 88080385: This API is not initialized. - 88080482: An invalid value or parameter occurs during the service. - 88080484: No permission. - 88080492: An error occurs when the service data packet is written. - 88080493: An error occurs when the service data packet is read. - 88080497: An error occurs when the internal logic of the service is executed. - -1: The underlying interface fails to be called.

Example

let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
}

let device: usbManager.USBDevice = devicesList[0];
usbManager.requestRight(device.name);
let devicepipe: usbManager.USBDevicePipe = usbManager.connectDevice(device);
let interfaces: usbManager.USBInterface = device.configs[0].interfaces[0];
let ret: number = usbManager.claimInterface(devicepipe, interfaces);
ret = usbManager.releaseInterface(devicepipe, interfaces);
console.log(`releaseInterface = ${ret}`);

usbManager.setConfiguration

setConfiguration(pipe: USBDevicePipe, config: USBConfiguration): number

Sets the device configuration.

1. Call usbManager.getDevices to obtain the USB device list and device configuration.
2. Call usbManager.requestRight to request the device access permission.
3. Call usbManager.connectDevice to obtain devicepipe as an input parameter.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
pipe	USBDevicePipe	Yes	USB device pipe, which is used to determine the bus number and device address. You need to call connectDevice to obtain its value.
config	USBConfiguration	Yes	USB configuration. You can use getDevices to obtain device information and identify the USB configuration based on the ID.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.

Return value

Type

Description

number

Returns 0 if the USB configuration is successfully set; returns an error code otherwise. The error codes are as follows: - 63: The data exceeds the expected maximum volume. - 88080385: This API is not initialized. - 88080482: An invalid value or parameter occurs during the service. - 88080484: No permission. - 88080492: An error occurs when the service data packet is written. - 88080493: An error occurs when the service data packet is read. - 88080497: An error occurs when the internal logic of the service is executed. - -1: The underlying interface fails to be called. - -17: I/O failure.

Example

let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
}

let device: usbManager.USBDevice = devicesList[0];
usbManager.requestRight(device.name);
let devicepipe: usbManager.USBDevicePipe = usbManager.connectDevice(device);
let config: usbManager.USBConfiguration = device.configs[0];
let ret: number= usbManager.setConfiguration(devicepipe, config);
console.log(`setConfiguration = ${ret}`);

usbManager.setInterface

setInterface(pipe: USBDevicePipe, iface: USBInterface): number

Sets a USB interface.

1. Call usbManager.getDevices to obtain the device list and interfaces.
2. Call usbManager.requestRight to request the device access permission.
3. Call usbManager.connectDevice to obtain devicepipe as an input parameter.
4. Call usbManager.claimInterface to register a communication interface.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
pipe	USBDevicePipe	Yes	USB device pipe, which is used to determine the bus number and device address. You need to call connectDevice to obtain its value.
iface	USBInterface	Yes	USB interface. You can use getDevices to obtain device information and identify the USB interface based on its id and alternateSetting.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.

Return value

Type

Description

number

Returns 0 if the USB interface is successfully set; returns an error code otherwise. The error codes are as follows: - 63: The data exceeds the expected maximum volume. - 88080385: This API is not initialized. - 88080482: An invalid value or parameter occurs during the service. - 88080484: No permission. - 88080492: An error occurs when the service data packet is written. - 88080493: An error occurs when the service data packet is read. - 88080497: An error occurs when the internal logic of the service is executed. - -1: The underlying interface fails to be called.

Example

let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
}

let device: usbManager.USBDevice = devicesList[0];
usbManager.requestRight(device.name);
let devicepipe: usbManager.USBDevicePipe = usbManager.connectDevice(device);
let interfaces: usbManager.USBInterface = device.configs[0].interfaces[0];
let ret: number = usbManager.claimInterface(devicepipe, interfaces);
ret = usbManager.setInterface(devicepipe, interfaces);
console.log(`setInterface = ${ret}`);

usbManager.getRawDescriptor

getRawDescriptor(pipe: USBDevicePipe): Uint8Array

Obtains the raw USB descriptor. If the USB service is abnormal, undefined may be returned. Check whether the return value of the API is empty.

1. Call usbManager.getDevices to obtain the USB device list.
2. Call usbManager.requestRight to request the device access permission.
3. Call usbManager.connectDevice to obtain devicepipe as an input parameter.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
pipe	USBDevicePipe	Yes	USB device pipe, which is used to determine the bus number and device address. You need to call connectDevice to obtain its value.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.

Return value

Type	Description
Uint8Array	Returns the raw USB descriptor if the operation is successful; returns undefined otherwise.

Example

let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
}

usbManager.requestRight(devicesList[0].name);
let devicepipe: usbManager.USBDevicePipe = usbManager.connectDevice(devicesList[0]);
let ret: Uint8Array = usbManager.getRawDescriptor(devicepipe);

usbManager.getFileDescriptor

getFileDescriptor(pipe: USBDevicePipe): number

Obtains the file descriptor.

1. Call usbManager.getDevices to obtain the USB device list.
2. Call usbManager.requestRight to request the device access permission.
3. Call usbManager.connectDevice to obtain devicepipe as an input parameter.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
pipe	USBDevicePipe	Yes	USB device pipe, which is used to determine the bus number and device address. You need to call connectDevice to obtain its value.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.

Return value

Type

Description

number

Returns the file descriptor corresponding to the device if this API is successful called; returns an error code otherwise. The error codes are as follows: - 63: The data exceeds the expected maximum volume. - 88080385: This API is not initialized. - 88080482: An invalid value or parameter occurs during the service. - 88080484: No permission. - 88080492: An error occurs when the service data packet is written. - 88080493: An error occurs when the service data packet is read. - 88080497: An error occurs when the internal logic of the service is executed. - -1: The underlying interface fails to be called.

Example

let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
}

usbManager.requestRight(devicesList[0].name);
let devicepipe: usbManager.USBDevicePipe = usbManager.connectDevice(devicesList[0]);
let ret: number = usbManager.getFileDescriptor(devicepipe);

usbManager.controlTransfer^(deprecated)

controlTransfer(pipe: USBDevicePipe, controlparam: USBControlParams, timeout ?: number): Promise<number>

Performs control transfer.

1. Call usbManager.getDevices to obtain the USB device list.
2. Call usbManager.requestRight to request the device access permission.
3. Call usbManager.connectDevice to obtain devicepipe as an input parameter.

NOTE

This API is supported since API version 9 and deprecated since API version 12. You are advised to use usbControlTransfer.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
pipe	USBDevicePipe	Yes	USB device pipe. You need to call connectDevice to obtain its value.
controlparam	USBControlParams	Yes	Control transfer parameters. Set the parameters as required. For details, see the USB protocol.
timeout	number	No	(Optional) Timeout duration, in ms. The default value is 0. You can set this parameter as required.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.

Return value

Type

Description

Promise<number>

Promise used to return the result, which is the size of the transferred or received data block if the transfer is successful. If the API call fails, the following error codes are returned: - 88080385: This API is not initialized. - 88080482: An invalid value or parameter occurs during the service. - 88080484: No permission. - 88080492: An error occurs when the service data packet is written. - 88080493: An error occurs when the service data packet is read. - 88080497: An error occurs when the internal logic of the service is executed. - -1: The underlying interface fails to be called.

Example

class PARA {
  request: number = 0
  reqType: usbManager.USBControlRequestType = 0
  target: usbManager.USBRequestTargetType = 0
  value: number = 0
  index: number = 0
  data: Uint8Array = new Uint8Array()
}

let param: PARA = {
  request: 0x06,
  reqType: 0x80,
  target:0,
  value: 0x01 << 8|0,
  index: 0,
  data: new Uint8Array(18)
};

let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
}

usbManager.requestRight(devicesList[0].name);
let devicepipe: usbManager.USBDevicePipe = usbManager.connectDevice(devicesList[0]);
usbManager.controlTransfer(devicepipe, param).then((ret: number) => {
console.log(`controlTransfer = ${ret}`);
})

usbManager.usbControlTransfer¹²⁺

usbControlTransfer(pipe: USBDevicePipe, requestparam: USBDeviceRequestParams, timeout ?: number): Promise<number>

Performs control transfer.

1. Call usbManager.getDevices to obtain the USB device list.
2. Call usbManager.requestRight to request the device access permission.
3. Call usbManager.connectDevice to obtain devicepipe as an input parameter.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
pipe	USBDevicePipe	Yes	USB device pipe, which is used to determine the USB device.
requestparam	USBDeviceRequestParams	Yes	Control transfer parameters. Set the parameters as required. For details, see the USB protocol.
timeout	number	No	(Optional) Timeout duration, in ms. The default value is 0, indicating no timeout.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error.Possible causes:1.Mandatory parameters are left unspecified.2.Incorrect parameter types.
801	Capability not supported.

Return value

Type

Description

Promise<number>

Promise used to return the result, which is the size of the transferred or received data block if the transfer is successful. If the API call fails, the following error codes are returned: - 88080385: This API is not initialized. - 88080482: An invalid value or parameter occurs during the service. - 88080484: No permission. - 88080492: An error occurs when the service data packet is written. - 88080493: An error occurs when the service data packet is read. - 88080497: An error occurs when the internal logic of the service is executed. - -1: The underlying interface fails to be called.

Example

class PARA {
  bmRequestType: number = 0
  bRequest: number = 0
  wValue: number = 0
  wIndex: number = 0
  wLength: number = 0
  data: Uint8Array = new Uint8Array()
}

let param: PARA = {
  bmRequestType: 0x80,
  bRequest: 0x06,

  wValue:0x01 << 8|0,
  wIndex: 0,
  wLength: 18,
  data: new Uint8Array(18)
};

let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
}

usbManager.requestRight(devicesList[0].name);
let devicepipe: usbManager.USBDevicePipe = usbManager.connectDevice(devicesList[0]);
usbManager.usbControlTransfer(devicepipe, param).then((ret: number) => {
console.log(`usbControlTransfer = ${ret}`);
})

usbManager.bulkTransfer

bulkTransfer(pipe: USBDevicePipe, endpoint: USBEndpoint, buffer: Uint8Array, timeout ?: number): Promise<number>

Performs bulk transfer.

1. Call usbManager.getDevices to obtain the USB device list and endpoints.
2. Call usbManager.requestRight to request the device access permission.
3. Call usbManager.connectDevice to obtain the returned devicepipe.
4. Obtain the usbManager.claimInterface API.
5. Call the usbManager.bulkTransfer API.

NOTE

The total amount of data (including pipe, endpoint, buffer, and timeout) transferred in bulk must be less than 200 KB.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
pipe	USBDevicePipe	Yes	USB device pipe. You need to call connectDevice to obtain its value.
endpoint	USBEndpoint	Yes	USB endpoint, which is used to determine the USB interface for data transfer. You need to call getDevices to obtain the device information list and endpoint. Wherein, address is used to determine the endpoint address, direction is used to determine the endpoint direction, and interfaceId is used to determine the USB interface to which the endpoint belongs. Other parameters are passed transparently.
buffer	Uint8Array	Yes	Buffer used to write or read data.
timeout	number	No	(Optional) Timeout duration, in ms. The default value is 0. You can set this parameter as required.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.

Return value

Type

Description

Promise<number>

Promise used to return the result, which is the size of the transferred or received data block if the transfer is successful. If the API call fails, the following error codes are returned: - 63: The data exceeds the expected maximum volume. - 88080385: This API is not initialized. - 88080482: An invalid value or parameter occurs during the service. - 88080484: No permission. - 88080492: An error occurs when the service data packet is written. - 88080493: An error occurs when the service data packet is read. - 88080497: An error occurs when the internal logic of the service is executed. - -1: The underlying interface fails to be called. - -3: The parameter is invalid. - -202: The device is not found.

Example

NOTE

The following sample code is only a basic process for calling the bulkTransfer API. In actual calling, you must comply with the device-related protocols to ensure correct data transfer and device compatibility.

// Call usbManager.getDevices to obtain a data set. Then, obtain a USB device and its access permission.
// Pass the obtained USB device as a parameter to usbManager.connectDevice. Then, call usbManager.connectDevice to connect the USB device.
// Call usbManager.claimInterface to claim a USB interface. After that, call usbManager.bulkTransfer to start bulk transfer.
let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
}

let device: usbManager.USBDevice = devicesList[0];
usbManager.requestRight(device.name);

let devicepipe: usbManager.USBDevicePipe = usbManager.connectDevice(device);
for (let i = 0; i < device.configs[0].interfaces.length; i++) {
  if (device.configs[0].interfaces[i].endpoints[0].attributes == 2) {
    let endpoint: usbManager.USBEndpoint = device.configs[0].interfaces[i].endpoints[0];
    let interfaces: usbManager.USBInterface = device.configs[0].interfaces[i];
    let ret: number = usbManager.claimInterface(devicepipe, interfaces);
    let buffer =  new Uint8Array(128);
    usbManager.bulkTransfer(devicepipe, endpoint, buffer).then((ret: number) => {
      console.log(`bulkTransfer = ${ret}`);
    });
  }
}

usbManager.usbSubmitTransfer¹⁸⁺

usbSubmitTransfer(transfer: UsbDataTransferParams): void

Requests a USB data transfer.

This API uses an asynchronous callback to return the result.

1. Call usbManager.getDevices to obtain the USB device list and endpoints.
2. Call usbManager.requestRight to request the device access permission.
3. Call usbManager.connectDevice to obtain the returned devicepipe.
4. Obtain the usbManager.claimInterface API.
5. Call the usbManager.usbSubmitTransfer API.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
transfer	UsbDataTransferParams	Yes	As a USB data transfer interface, it is required for a client to initiate a transfer request.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types.
801	Capability not supported.
14400001	Access right denied. Call requestRight to get the USBDevicePipe access right first.
14400007	Resource busy.
14400008	No such device (it may have been disconnected).
14400009	Insufficient memory.
14400012	Transmission I/O error.

Example

NOTE

The following sample code shows the basic process for calling the usbSubmitTransfer API and it needs to be executed in a specific method. In actual calling, you must comply with the device-related protocols to ensure correct data transfer and device compatibility.

// Call usbManager.getDevices to obtain a data set. Then, obtain a USB device and its access permission.
// Pass the obtained USB device as a parameter to usbManager.connectDevice. Then, call usbManager.connectDevice to connect the USB device.
// Call usbManager.claimInterface to claim a USB interface. After that, call usbManager.bulkTransfer to start bulk transfer.
let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
  return;
}
let device: usbManager.USBDevice = devicesList[0];
usbManager.requestRight(device.name);
let devicepipe: usbManager.USBDevicePipe = usbManager.connectDevice(device);
// Obtain the endpoint address.
let endpoint = device.configs[0].interfaces[0]?.endpoints.find((value) => {
  return value.direction === 0 && value.type === 2
})
// Obtain the first ID of the device.
let ret: number = usbManager.claimInterface(devicepipe, device.configs[0].interfaces[0], true);

let transferParams: usbManager.UsbDataTransferParams = {
  devPipe: devicepipe,
  flags: usbManager.UsbTransferFlags.USB_TRANSFER_SHORT_NOT_OK,
  endpoint: 1,
  type: usbManager.UsbEndpointTransferType.TRANSFER_TYPE_BULK,
  timeout: 2000,
  length: 10, 
  callback: () => {},
  userData: new Uint8Array(10),
  buffer: new Uint8Array(10),
  isoPacketCount: 0,
};
try {
  transferParams.endpoint=endpoint?.address as number;
  transferParams.callback=(err, callBackData: usbManager.SubmitTransferCallback)=>{
    console.info('callBackData =' +JSON.stringify(callBackData));
  }
  usbManager.usbSubmitTransfer(transferParams); 
  console.info('USB transfer request submitted.');
} catch (error) {
  console.error('USB transfer failed:', error);
}

usbManager.usbCancelTransfer¹⁸⁺

usbCancelTransfer(transfer: UsbDataTransferParams): void

Cancels an asynchronous USB data transfer request.

1. Call usbManager.getDevices to obtain the USB device list and endpoints.
2. Call usbManager.requestRight to request the device access permission.
3. Call usbManager.connectDevice to obtain the returned devicepipe.
4. Obtain the usbManager.claimInterface API.
5. Call the usbManager.usbCancelTransfer API.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
transfer	UsbDataTransferParams	Yes	Only USBDevicePipe and endpoint are required for canceling the transfer.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1.Mandatory parameters are left unspecified. 2.Incorrect parameter types.
801	Capability not supported.
14400001	Access right denied. Call requestRight to get the USBDevicePipe access right first.
14400008	No such device (it may have been disconnected).
14400010	Other USB error. Possible causes: 1.Unrecognized discard error code.
14400011	The transfer is not in progress, or is already complete or cancelled.

Return value

Type	Description
<void>	None.

Example

NOTE

The following sample code shows the basic process for calling the usbCancelTransfer API and it needs to be executed in a specific method. In actual calling, you must comply with the device-related protocols to ensure correct data transfer and device compatibility.

// Call usbManager.getDevices to obtain a data set. Then, obtain a USB device and its access permission.
// Pass the obtained USB device as a parameter to usbManager.connectDevice. Then, call usbManager.connectDevice to connect the USB device.
// Call usbManager.claimInterface to claim a USB interface. After that, call usbManager.bulkTransfer to start bulk transfer.
let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
  return;
}
let device: usbManager.USBDevice = devicesList[0];
usbManager.requestRight(device.name);
let devicepipe: usbManager.USBDevicePipe = usbManager.connectDevice(device);
// Obtain the endpoint address.
let endpoint = device.configs[0].interfaces[0]?.endpoints.find((value) => {
  return value.direction === 0 && value.type === 2
})
// Obtain the first ID of the device.
let ret: number = usbManager.claimInterface(devicepipe, device.configs[0].interfaces[0], true);
let transferParams: usbManager.UsbDataTransferParams = {
  devPipe: devicepipe,
  flags: usbManager.UsbTransferFlags.USB_TRANSFER_SHORT_NOT_OK,
  endpoint: 1,
  type: usbManager.UsbEndpointTransferType.TRANSFER_TYPE_BULK,
  timeout: 2000,
  length: 10, 
  callback: () => {},
  userData: new Uint8Array(10),
  buffer: new Uint8Array(10),
  isoPacketCount: 0,
};
try {
  transferParams.endpoint=endpoint?.address as number;
  transferParams.callback=(err, callBackData: usbManager.SubmitTransferCallback)=>{
    console.info('callBackData =' +JSON.stringify(callBackData));
  }
  usbManager.usbSubmitTransfer(transferParams);
  usbManager.usbCancelTransfer(transferParams);
  console.info('USB transfer request submitted.');
} catch (error) {
  console.error('USB transfer failed:', error);
}

usbManager.closePipe

closePipe(pipe: USBDevicePipe): number

Closes a USB device pipe.

1. Call usbManager.getDevices to obtain the USB device list.
2. Call usbManager.requestRight to request the device access permission.
3. Call usbManager.connectDevice to obtain devicepipe as an input parameter.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
pipe	USBDevicePipe	Yes	USB device pipe, which is used to determine the message control channel. You need to call connectDevice to obtain its value.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.

Return value

Type

Description

number

Returns 0 if the USB device pipe is closed successfully; returns an error code otherwise. The error codes are as follows: - 63: The data exceeds the expected maximum volume. - 88080393: An error occurs when the API data packet is read. - 88080482: An invalid value or parameter occurs during the service. - 88080484: No permission. - 88080493: An error occurs when the service data packet is read. - 88080497: An error occurs when the internal logic of the service is executed. - -1: The underlying interface fails to be called.

Example

let devicesList: Array<usbManager.USBDevice> = usbManager.getDevices();
if (devicesList.length == 0) {
  console.log(`device list is empty`);
}

usbManager.requestRight(devicesList[0].name);
let devicepipe: usbManager.USBDevicePipe = usbManager.connectDevice(devicesList[0]);
let ret: number = usbManager.closePipe(devicepipe);
console.log(`closePipe = ${ret}`);

usbManager.hasAccessoryRight¹⁴⁺

hasAccessoryRight(accessory: USBAccessory): boolean

Checks whether the application has the permission to access the USB accessory.

You need to call usbManager.getAccessoryList to obtain the accessory list and use USBAccessory as a parameter.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
accessory	USBAccessory	Yes	USB accessory.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.
14400004	Service exception. Possible causes: 1. No accessory is plugged in.
14400005	Database operation exception.
14401001	The target USBAccessory not matched.

Return value

Type	Description
boolean	The value true indicates that the application has the permission to access the USB accessory; false indicates the opposite.

Example

import { hilog } from '@kit.PerformanceAnalysisKit';
try {
  let accList: usbManager.USBAccessory[] = usbManager.getAccessoryList()
  let flag = usbManager.hasAccessoryRight(accList[0])
  hilog.info(0, 'testTag ui', `hasAccessoryRight success, ret:${flag}`)
} catch (error) {
  hilog.info(0, 'testTag ui', `hasAccessoryRight error ${error.code}, message is ${error.message}`)
}

usbManager.requestAccessoryRight¹⁴⁺

requestAccessoryRight(accessory: USBAccessory): Promise<boolean>

Requests the permission to access a USB accessory for a specified application.

You need to call usbManager.getAccessoryList to obtain the accessory list and use USBAccessory as a parameter.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
accessory	USBAccessory	Yes	USB accessory.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.
14400004	Service exception. Possible causes: 1. No accessory is plugged in.
14400005	Database operation exception.
14401001	The target USBAccessory not matched.

Return value

Type	Description
Promise<boolean>	Promise used to return the application result. The value true indicates that the device access permissions are granted; false indicates the opposite.

Example

import { hilog } from '@kit.PerformanceAnalysisKit';
try {
  let accList: usbManager.USBAccessory[] = usbManager.getAccessoryList()
  let flag = usbManager.requestAccessoryRight(accList[0])
  hilog.info(0, 'testTag ui', `requestAccessoryRight success, ret:${flag}`)
} catch (error) {
  hilog.info(0, 'testTag ui', `requestAccessoryRight error ${error.code}, message is ${error.message}`)
}

usbManager.cancelAccessoryRight¹⁴⁺

cancelAccessoryRight(accessory: USBAccessory): void

Cancels the permission of the current application to access USB accessories.

You need to call usbManager.getAccessoryList to obtain the accessory list and use USBAccessory as a parameter.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
accessory	USBAccessory	Yes	USB accessory.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.
14400004	Service exception. Possible causes: 1. No accessory is plugged in.
14400005	Database operation exception.
14401001	The target USBAccessory not matched.

Example

import { hilog } from '@kit.PerformanceAnalysisKit';
try {
  let accList: usbManager.USBAccessory[] = usbManager.getAccessoryList()
  let flag = usbManager.requestAccessoryRight(accList[0])
  usbManager.cancelAccessoryRight(accList[0])
  hilog.info(0, 'testTag ui', `cancelAccessoryRight success`)
} catch (error) {
  hilog.info(0, 'testTag ui', `cancelAccessoryRight error ${error.code}, message is ${error.message}`)
}

usbManager.getAccessoryList¹⁴⁺

getAccessoryList(): Array<Readonly<USBAccessory>>

Obtains the list of USB accessories connected to the host.

System capability: SystemCapability.USB.USBManager

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
801	Capability not supported.
14400004	Service exception. Possible causes: 1. No accessory is plugged in.

Return value

Type	Description
Array<Readonly<USBAccessory>>	List of USB accessories (read-only). Currently, only one USB accessory is contained in the list.

Example

import { hilog } from '@kit.PerformanceAnalysisKit';
try {
  let accList: usbManager.USBAccessory[] = usbManager.getAccessoryList()
  hilog.info(0, 'testTag ui', `getAccessoryList success, accList: ${JSON.stringify(accList)}`)
} catch (error) {
  hilog.info(0, 'testTag ui', `getAccessoryList error ${error.code}, message is ${error.message}`)
}

usbManager.openAccessory¹⁴⁺

openAccessory(accessory: USBAccessory): USBAccessoryHandle

Obtains the accessory handle and opens the accessory file descriptor.

You need to call usbManager.getAccessoryList to obtain the accessory list and use USBAccessory as a parameter.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
accessory	USBAccessory	Yes	USB accessory.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.
14400001	Permission denied. Call requestAccessoryRight to get the right first.
14400004	Service exception. Possible causes: 1. No accessory is plugged in.
14401001	The target USBAccessory not matched.
14401002	Failed to open the native accessory node.
14401003	Cannot reopen the accessory.

Return value

Type	Description
USBAccessoryHandle	USB accessory handle.

Example

import { hilog } from '@kit.PerformanceAnalysisKit';
try {
  let accList: usbManager.USBAccessory[] = usbManager.getAccessoryList()
  let flag = usbManager.requestAccessoryRight(accList[0])
  let handle = usbManager.openAccessory(accList[0])
  hilog.info(0, 'testTag ui', `openAccessory success`)
} catch (error) {
  hilog.info(0, 'testTag ui', `openAccessory error ${error.code}, message is ${error.message}`)
}

usbManager.closeAccessory¹⁴⁺

closeAccessory(accessoryHandle: USBAccessoryHandle): void

Closes the accessory file descriptor.

You need to call usbManager.openAccessory to obtain the accessory list and use USBAccessoryHandle as a parameter.

System capability: SystemCapability.USB.USBManager

Parameters

Name	Type	Mandatory	Description
accessoryHandle	USBAccessoryHandle	Yes	USB accessory handle, obtained through openAccessory.

Error codes

For details about the error codes, see USB Service Error Codes.

ID	Error Message
401	Parameter error. Possible causes: 1. Mandatory parameters are left unspecified. 2. Incorrect parameter types.
801	Capability not supported.
14400004	Service exception. Possible causes: 1. No accessory is plugged in.

Example

import { hilog } from '@kit.PerformanceAnalysisKit';
try {
  let accList: usbManager.USBAccessory[] = usbManager.getAccessoryList()
  let flag = usbManager.requestAccessoryRight(accList[0])
  let handle = usbManager.openAccessory(accList[0])
  usbManager.closeAccessory(handle)
  hilog.info(0, 'testTag ui', `closeAccessory success`)
} catch (error) {
  hilog.info(0, 'testTag ui', `closeAccessory error ${error.code}, message is ${error.message}`)
}

USBEndpoint

Represents the USB endpoint from which data is sent or received. You can obtain the USB endpoint through USBInterface.

System capability: SystemCapability.USB.USBManager

Name	Type	Mandatory	Description
address	number	Yes	Endpoint address.
attributes	number	Yes	Endpoint attributes.
interval	number	Yes	Endpoint interval.
maxPacketSize	number	Yes	Maximum size of data packets on the endpoint.
direction	USBRequestDirection	Yes	Endpoint direction.
number	number	Yes	Endpoint number.
type	number	Yes	Endpoint type.
interfaceId	number	Yes	Unique ID of the interface to which the endpoint belongs.

USBInterface

Represents a USB interface. One USBConfiguration object can contain multiple USBInterface instances, each providing a specific function.

System capability: SystemCapability.USB.USBManager

Name	Type	Mandatory	Description
id	number	Yes	Unique ID of the USB interface.
protocol	number	Yes	Interface protocol.
clazz	number	Yes	Device type.
subClass	number	Yes	Device subclass.
alternateSetting	number	Yes	Settings for alternating between descriptors of the same USB interface.
name	string	Yes	Interface name.
endpoints	Array<USBEndpoint>	Yes	Endpoints that belong to the USB interface.

USBConfiguration

Represents the USB configuration. One USBDevice can contain multiple USBConfig instances.

System capability: SystemCapability.USB.USBManager

Name	Type	Mandatory	Description
id	number	Yes	Unique ID of the USB configuration.
attributes	number	Yes	Configuration attributes.
maxPower	number	Yes	Maximum power consumption, in mA.
name	string	Yes	Configuration name, which can be left empty.
isRemoteWakeup	boolean	Yes	Support for remote wakeup.
isSelfPowered	boolean	Yes	Support for independent power supplies.
interfaces	Array <USBInterface>	Yes	Supported interface attributes.

USBDevice

Represents the USB device information.

System capability: SystemCapability.USB.USBManager

Name	Type	Mandatory	Description
busNum	number	Yes	Bus address.
devAddress	number	Yes	Device address.
serial	string	Yes	Sequence number.
name	string	Yes	Device name.
manufacturerName	string	Yes	Device manufacturer.
productName	string	Yes	Product name.
version	string	Yes	Version number.
vendorId	number	Yes	Vendor ID.
productId	number	Yes	Product ID.
clazz	number	Yes	Device class.
subClass	number	Yes	Device subclass.
protocol	number	Yes	Device protocol code.
configs	Array<USBConfiguration>	Yes	Device configuration descriptor information.

USBDevicePipe

Represents a USB device pipe, which is used to determine a USB device.

System capability: SystemCapability.USB.USBManager

Name	Type	Mandatory	Description
busNum	number	Yes	Bus address.
devAddress	number	Yes	Device address.

USBControlParams^(deprecated)

Represents control transfer parameters.

NOTE

This API is supported since API version 9 and deprecated since API version 18. You are advised to use USBDeviceRequestParams instead.

System capability: SystemCapability.USB.USBManager

Name	Type	Mandatory	Description
request	number	Yes	Request type.
target	USBRequestTargetType	Yes	Request target type.
reqType	USBControlRequestType	Yes	Control request type.
value	number	Yes	Request parameter.
index	number	Yes	Index of the request parameter.
data	Uint8Array	Yes	Buffer for writing or reading data.

USBDeviceRequestParams¹²⁺

Represents control transfer parameters.

System capability: SystemCapability.USB.USBManager

Name	Type	Mandatory	Description
bmRequestType	number	Yes	Control request type.
bRequest	number	Yes	Request type.
wValue	number	Yes	Request parameter.
wIndex	number	Yes	Index of the request parameter.
wLength	number	Yes	Length of the requested data.
data	Uint8Array	Yes	Buffer for writing or reading data.

USBRequestTargetType

Enumerates request target types.

System capability: SystemCapability.USB.USBManager

Name	Value	Description
USB_REQUEST_TARGET_DEVICE	0	Device.
USB_REQUEST_TARGET_INTERFACE	1	Interface.
USB_REQUEST_TARGET_ENDPOINT	2	Endpoint.
USB_REQUEST_TARGET_OTHER	3	Other.

USBControlRequestType

Enumerates control request types.

System capability: SystemCapability.USB.USBManager

Name	Value	Description
USB_REQUEST_TYPE_STANDARD	0	Standard.
USB_REQUEST_TYPE_CLASS	1	Class.
USB_REQUEST_TYPE_VENDOR	2	Vendor.

USBRequestDirection

Enumerates request directions.

System capability: SystemCapability.USB.USBManager

Name	Value	Description
USB_REQUEST_DIR_TO_DEVICE	0	Request for writing data from the host to the device.
USB_REQUEST_DIR_FROM_DEVICE	0x80	Request for reading data from the device to the host.

USBAccessory¹⁴⁺

Describes the USB accessory information.

System capability: SystemCapability.USB.USBManager

Name	Type	Mandatory	Description
manufacturer	string	Yes	Manufacturer of an accessory.
product	string	Yes	Product type of an accessory.
description	string	Yes	Description of an accessory.
version	string	Yes	Version of an accessory.
serialNumber	string	Yes	SN of an accessory.

USBAccessoryHandle¹⁴⁺

Describes the USB accessory handle.

System capability: SystemCapability.USB.USBManager

Name	Type	Mandatory	Description
accessoryFd	number	Yes	Accessory file descriptor. A valid accessoryFd is a positive integer.

UsbDataTransferParams¹⁸⁺

As a USB data transfer interface, it is required for a client to initiate a transfer request.

System capability: SystemCapability.USB.USBManager

Name	Type	Mandatory	Description
devPipe	USBDevicePipe	Yes	USB device pipe, which is used to determine the bus number and device address. You need to call connectDevice to obtain its value.
flags	UsbTransferFlags	Yes	USB transfer flag.
endpoint	number	Yes	Endpoint address, which is a positive integer.
type	UsbEndpointTransferType	Yes	Transfer type.
timeout	number	Yes	Timeout duration, in ms.
length	number	Yes	Length of the data buffer, in bytes. The value must be a non-negative number (expected length).
callback	AsyncCallback<SubmitTransferCallback>	Yes	Information returned by the callback.
userData	Uint8Array	Yes	User data.
buffer	Uint8Array	Yes	Buffer, which is used to store data for read or write requests.
isoPacketCount	number	Yes	Number of data packets during real-time transfer, used only for I/Os with real-time transfer endpoints. The value must be a non-negative number.

UsbTransferFlags¹⁸⁺

Enumerates USB transfer flags.

System capability: SystemCapability.USB.USBManager

Name	Value	Description
USB_TRANSFER_SHORT_NOT_OK	0	Reports short frames as errors.
USB_TRANSFER_FREE_BUFFER	1	Automatically releases the transfer buffer.
USB_TRANSFER_FREE_TRANSFER	2	Automatically transfers after the callback is complete.
USB_TRANSFER_ADD_ZERO_PACKET	3	Adds an additional data packet to the transfer.

UsbEndpointTransferType¹⁸⁺

Enumerates USB transfer types.

System capability: SystemCapability.USB.USBManager

Name	Value	Description
TRANSFER_TYPE_ISOCHRONOUS	0x1	Real-time transfer.
TRANSFER_TYPE_BULK	0x2	Performs bulk transfer.
TRANSFER_TYPE_INTERRUPT	0x3	Interrupt transfer.

SubmitTransferCallback¹⁸⁺

Transfers USB data packets in an asynchronous manner.

System capability: SystemCapability.USB.USBManager

Name	Type	Mandatory	Description
actualLength	number	Yes	Actual length of the read or written data, in bytes.
status	UsbTransferStatus	Yes	Status after reading or writing is complete.
isoPacketDescs	Array<Readonly<UsbIsoPacketDescriptor>>	Yes	Packet information transferred in real time.

UsbTransferStatus¹⁸⁺

Enumerates the statuses returned by libusb through callback after the actual processing is complete.

System capability: SystemCapability.USB.USBManager

Name	Value	Description
TRANSFER_COMPLETED	0	Transfer completed.
TRANSFER_ERROR	1	Transfer failed.
TRANSFER_TIMED_OUT	2	Transfer timeout.
TRANSFER_CANCELED	3	Transfer canceled.
TRANSFER_STALL	4	Transfer stalled (at bulk/interrupt endpoint).
TRANSFER_NO_DEVICE	5	Device disconnected.
TRANSFER_OVERFLOW	6	Data overflow.

UsbIsoPacketDescriptor¹⁸⁺

Describes packet information returned in real time by the transfer callback.

System capability: SystemCapability.USB.USBManager

Name	Type	Mandatory	Description
length	number	Yes	Expected length of the read or written data, in bytes.
actualLength	number	Yes	Actual length of the read or written data, in bytes.
status	UsbTransferStatus	Yes	Status returned by callback.

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